Alert archive / Pennsylvania / Severe Thunderstorm Watches in 2018
Severe Thunderstorm Watch 312
The Storm Prediction Center issued this severe thunderstorm watch at Jul 27, 2018, 1:17 PM EDT for 5 states. It was in force for 9 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 27, 2018, 1:17 PM EDT (17:17 UTC)
- Expired
- Jul 27, 2018, 10:00 PM EDT
- In force
- 9 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 55 kt
All 74 counties
Capitol Planning Region, CT, Greater Bridgeport Planning Region, CT, Naugatuck Valley Planning Region, CT, Northwest Hills Planning Region, CT, Berkshire County, MA, Franklin County, MA, Hampden County, MA, Hampshire County, MA, Atlantic County, NJ, Bergen County, NJ, Burlington County, NJ, Camden County, NJ, Cape May County, NJ, Cumberland County, NJ, Essex County, NJ, Gloucester County, NJ, Hudson County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ, Morris County, NJ, Ocean County, NJ, Passaic County, NJ, Salem County, NJ, Somerset County, NJ, Sussex County, NJ, Union County, NJ, Warren County, NJ, Albany County, NY, Bronx County, NY, Columbia County, NY, Delaware County, NY, Dutchess County, NY, Greene County, NY, Kings County, NY, Nassau County, NY, New York County, NY, Orange County, NY, Putnam County, NY, Queens County, NY, Rensselaer County, NY, Richmond County, NY, Rockland County, NY, Saratoga County, NY, Schenectady County, NY, Schoharie County, NY, Sullivan County, NY, Ulster County, NY, Washington County, NY, Westchester County, NY, Adams County, PA, Berks County, PA, Bucks County, PA, Carbon County, PA, Chester County, PA, Cumberland County, PA, Dauphin County, PA, Delaware County, PA, Franklin County, PA, Lackawanna County, PA, Lancaster County, PA, Lebanon County, PA, Lehigh County, PA, Luzerne County, PA, Monroe County, PA, Montgomery County, PA, Northampton County, PA, Perry County, PA, Philadelphia County, PA, Pike County, PA, Schuylkill County, PA, Wayne County, PA, York County, PA
The radar
The Philadelphia radar (KDIX), 136 km from the middle of the area, began a volume at 17:20 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 5%
- One or more EF2 to EF5 tornadoes
- 2%
- Ten or more severe wind reports
- 40%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 20%
- One or more hailstones of 2 inches or more
- 20%
- Six or more combined severe hail and wind reports
- 60%
Warnings issued inside it
28 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 27, 1:56 PM EDT | Severe Thunderstorm Warning | ALY | Albany, Rensselaer, Saratoga, Washington | 64 min |
| Jul 27, 2:03 PM EDT | Severe Thunderstorm Warning | ALY | Albany, Rensselaer, Saratoga | 27 min |
| Jul 27, 2:04 PM EDT | Severe Thunderstorm Warning | PHI | Morris, Somerset | 41 min |
| Jul 27, 2:14 PM EDT | Severe Thunderstorm Warning | PHI | Cumberland, Salem | 46 min |
| Jul 27, 2:59 PM EDT | Severe Thunderstorm Warning | PHI | Cumberland, Salem | 46 min |
| Jul 27, 3:11 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Lehigh | 49 min |
| Jul 27, 3:12 PM EDT | Severe Thunderstorm Warning | ALY | Northwest Hills Planning Region | 51 min |
| Jul 27, 3:54 PM EDT | Flash Flood Warning | PHI | Berks | 4 hr |
| Jul 27, 4:18 PM EDT | Severe Thunderstorm Warning | PHI | Atlantic, Cape May, Cumberland, Gloucester, Salem | 42 min |
| Jul 27, 4:19 PM EDT | Flash Flood Warning | PHI | Cumberland | 4 hr |
| Jul 27, 4:25 PM EDT | Flash Flood Warning | OKX | Essex, Hudson, Union | 95 min |
| Jul 27, 4:32 PM EDT | Severe Thunderstorm Warning | PHI | Middlesex, Somerset | 43 min |
| Jul 27, 4:43 PM EDT | Severe Thunderstorm Warning | BOX | Franklin | 32 min |
| Jul 27, 4:45 PM EDT | Severe Thunderstorm Warning | OKX | Essex, Hudson, Union | 45 min |
| Jul 27, 4:49 PM EDT | Severe Thunderstorm Warning | ALY | Columbia, Dutchess, Greene, Ulster | 56 min |
| Jul 27, 4:51 PM EDT | Severe Thunderstorm Warning | ALY | Albany, Montgomery, Schenectady, Schoharie | 39 min |
| Jul 27, 4:54 PM EDT | Flash Flood Warning | PHI | Middlesex | 4 hr |
| Jul 27, 5:00 PM EDT | Flash Flood Warning | PHI | Monroe | 3 hr |
| Jul 27, 5:14 PM EDT | Severe Thunderstorm Warning | OKX | Kings, New York, Queens | 35 min |
| Jul 27, 5:23 PM EDT | Severe Thunderstorm Warning | ALY | Northwest Hills Planning Region | 67 min |
| Jul 27, 6:03 PM EDT | Severe Thunderstorm Warning | PHI | Chester | 42 min |
| Jul 27, 6:06 PM EDT | Severe Thunderstorm Warning | CTP | Lancaster | 54 min |
| Jul 27, 6:16 PM EDT | Flash Flood Warning | OKX | Hudson, Union | 3 hr |
| Jul 27, 6:40 PM EDT | Severe Thunderstorm Warning | PHI | Berks | 50 min |
| Jul 27, 7:03 PM EDT | Flash Flood Warning | PHI | Berks | 3 hr |
| Jul 27, 7:06 PM EDT | Severe Thunderstorm Warning | CTP | Lancaster | 24 min |
| Jul 27, 7:09 PM EDT | Severe Thunderstorm Warning | PHI | Chester | 51 min |
| Jul 27, 8:11 PM EDT | Severe Thunderstorm Warning | BOX | Franklin, Worcester | 28 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Brookhaven, NY (KOKX), launched 12:00Z, 5.3 hours before the alert went out and 194 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 752 J/kg
- Mixed-layer CIN
- -30 J/kg
- Mixed-layer LCL
- 998 m above ground
- 0-6 km bulk shear
- 37 kt
- 0-1 km storm-relative helicity
- 37 m²/s²
- 0-3 km storm-relative helicity
- 53 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 1.5
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 27, 12:59 PM EDT | Mesoscale Discussion | SPC | 91 min | |
| Jul 27, 4:50 PM EDT | Mesoscale Discussion | SPC | 55 min | |
| Jul 27, 7:06 PM EDT | Mesoscale Discussion | SPC | 54 min | |
| Jul 27, 1:31 PM EDT | Severe Thunderstorm Watch | SPC | Middlesex, Worcester | 8 hr |
Nearby
Severe Thunderstorm Watches in Pennsylvania, 2018Severe Thunderstorm Watches in New York, 2018Severe Thunderstorm Watches in New Jersey, 2018Every severe thunderstorm watch in 2018
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.